long running processes - MySQL - can I limit the maximum time allowed for a query to run?

Question

I'm looking for a way to limit the max running time of a query on mysql server. I figured this could be done through the my.cnf configuration file, but couldn't find anything relevant in the docs. Anyone knows if this could be done? thanks.

Answer 1

Update

As of MySQL 5.7, you can include a MAX_EXECUTION_TIME optimizer hint in your SELECT queries to instruct the server to terminate it after the specified time.

As far as I know, if you want to enforce a server-wide timeout, or if you care about queries besides SELECTs, the original answer is still your only option.

Original answer

There is no way to specify a maximum run time when sending a query to the server to run.

However, it is not uncommon to have a cron job that runs every second on your database server, connecting and doing something like this:

1. SHOW PROCESSLIST
2. Find all connections with a query time larger than your maximum desired time
3. Run KILL [process id] for each of those processes